The present invention refers to a method for making dental and jaw models. The models comprise a base section and removable tooth or casting mold section which are removably secured by pins put into suitable holes in the base.
German Patent No. 2,125,927 discloses method, for making dental models whereby at least two pins are used for every section on the one hand and on the other hand A variant to the two pin method provides no means for easily separating the sections from the base. At the time of filing of German Patent No. 2,125,927 the provision of two pins brought some advantages with reference to the then known prior art by achieving a better guide and a more exact insertion of the tooth sections, whereby a bushing is provided for each pin. Two disadvantages of the method of German Patent No. 2,125,927 are the costs for the material it is therefor to parallelly guide exactly and the two corresponding holes.
German Patent No. 1,088,188 refers to a device for non-rotatably and interchangeably fastening a single supporting pin for a single artificial tooth in a working model. The reference discloses single teeth replacement parts which are fastened removably with a single pin in the working model. All disclosed pins are conical, and have a section departing from the circular form, e.g. a square, triangular or multiangular section. The use of pins with such a cross-section prevents rotation. However, the use of method conical pins introduces the danger that gypsum particles, which can pass between the two conical surfaces of the pin and the hole respectively, will impair the accuracy and the seat.
While pulling out a tooth section from the base for the first time after casting, difficulties can arise and lead to the need for the use of a great force. For solving this problem, the U.S. Pat. No. 3,498,580 proposes to provide the base with window-shaped openings, in which a tool can be inserted for lifting off each tooth section. This brings an additional complication for the production of the base and the model, and a weakening of the base.